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Subject: [OMPI users] Xgrid and choosing agents...
From: Klymak Jody (jklymak_at_[hidden])
Date: 2009-07-11 10:56:08

Hi all,

Sorry in advance if these are naive questions - I'm not experienced in
running a grid...

I'm using openMPI on 4 duo Quad-core Xeon xserves. The 8 cores mimic
16 cores and show up in xgrid as each agent having 16 processors.
However, the processing speed goes down as the used processors exceeds
8, so if possible I'd prefer to not have more than 8 processors
working on each machine at a time.

Unfortunately, if I submit a 16-processor job to xgrid it all goes to
"xserve03". Or even worse, it does so if I submit two separate 8-
processor jobs. Is there anyway to steer jobs to less-busy agents?

I tried making a hostfile and then specifying the host, but I get:

/usr/local/openmpi/bin/mpirun -n 8 --hostfile hostfile --host
xserve01.local ../build/mitgcmuv

Some of the requested hosts are not included in the current allocation
for the
The requested hosts were:

so I assume --host doesn't work with xgrid?

Is a reasonable alternative to simply not use xgrid and rely on ssh?

Thanks, Jody

Jody Klymak